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Thursday, March 31, 2011

Acute Coronary Syndrome

A 49-year-old man is evaluated in the emergency department for chest discomfort accompanied by nausea and dyspnea that began 2 hours ago. On physical examination, blood pressure is 109/78 mm Hg and heart rate is 88/min. There is no jugular venous distention and no carotid bruits. The lungs are clear. Cardiac examination shows a normal S1 and S2 and no gallops, rubs, or murmurs. The troponin level is 6 ng/mL (normal <0.5 ng/mL). Electrocardiogram shows a 1-mV ST elevation in leads II, III, and aVF.

He is treated with enoxaparin, aspirin, metoprolol, and glycoprotein receptor blockers and is taken to the cardiac catheterization laboratory. A stent is placed in a subtotally occluded right coronary artery. A follow-up echocardiogram shows normal wall motion, normal valve function, and a normal ejection fraction. By day 4, he has no complications and is prepared to be discharged.

In addition to aspirin, clopidogrel, and metoprolol, which of the following medications should be given at discharge?
A Atorvastatin
B Gemfibrozil
C Niacin
D Warfarin

Key Point
In patients with an acute coronary syndrome, statin therapy is indicated regardless of the serum cholesterol level.

Answer and Critique (Correct Answer = A)

This patient has survived a small inferior wall myocardial infarction and was successfully treated with a stent. At discharge, he should receive aspirin, metoprolol, clopidogrel for at least 180 days, and a statin regardless of his serum cholesterol level. In patients with coronary artery disease, especially those presenting with symptoms and those undergoing revascularization by either stenting or bypass graft surgery, statin therapy reduces late cardiovascular events despite having minimal or no effect on the angiographic appearance of the coronary arteries.

The PROVE IT-TIMI 22 study compared a moderate-dose statin (pravastatin, 40 mg/d) with a high-dose statin (atorvastatin, 80 mg/d) in patients hospitalized for acute coronary syndrome. The median LDL cholesterol levels achieved were 95 mg/dL by the pravastatin group and 62 mg/dL for the atorvastatin group. Those receiving atorvastatin had a 16% reduction in the composite endpoint of death from any cause, myocardial infarction, unstable angina requiring rehospitalization, coronary artery revascularization, and stroke during 2 years of follow-up. These results showed evidence of benefit from early aggressive LDL cholesterol lowering with high-dose atorvastatin.

Warfarin is not indicated after ST-elevation myocardial infarction treated by stenting unless there is another indication such as atrial fibrillation, deep venous thrombosis, or intracardiac thrombus.

Niacin for hypertriglyceridemia may be needed, but at this time the triglyceride values are not reported and may be falsely elevated early in the course of ST-elevation myocardial infarction. The first line of treatment would be statins even for normal LDL cholesterol levels in patients with documented coronary artery disease. The combination of statins with a fibrate (e.g., gemfibrozil) is attractive for patients who have both high cholesterol and triglyceride levels or for those who continue to have elevated triglyceride levels after reaching their LDL cholesterol target on statin therapy. However, in this patient, the best initial choice is a statin.
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